Bio-inspired superhydrophobic wood with high stability and durability constructed by using synergies of furfural resin and nano-TiO2

Stable super-hydrophobic modification can extend wood service life and expand its application. Inspired by lotus leaf effects, this study proposed a new environmentally friendly strategy by using biomass-derived furfuryl alcohol (FA) and nano-particles based on organic-inorganic hybridization. The FA was pre-polymerized on wood surface followed by in situ growth of stearic acid modified nano-TiO2. The modified wood (PFT) behaved super-hydrophobic, and the water contact angle and rolling angle reached 157° and 3.2°. This was mainly because a micro-nano, coral-like and rough structure was fabricated on wood surface with hydrophobic furfural resin, suggested by SEM, AFM and FTIR results. The PFT presented prominent durable super-hydrophobicity after mechanical abrasion, tape peeling and acid destruction owing to the fixation effects from furfural resin on nano-TiO2. The dimensional stability was remarkably improved and the volumetric change after 24 h water absorption decreased by about 90 %. This was primarily because ① super-hydrophobic wood had low attraction to water molecules, ② most water paths were blocked by hydrophobic modifiers, ③ some cell walls were bulked and many sorption sites became inaccessible. Besides, the PFT exhibited excellent self-cleaning performances and improved surface hardness and thermal stability. Such stable and durable super-hydrophobic material may have long service life and meet demands for application under harsh environments.